Im using the Tunze ato and never had any problems with it. I flipped over the floater sensor and polaced it at the bottom of my top off tank. It will go off when the water gets down to about an inch so I know I need to change it.

Got anything in place to prevent failure?

That's a disaster waiting to happen. :twised:

Well I finally got around to making room under my stand for the ato reservoir. Today I got the hydor ato with an eheim compact 600 pump installed and so far I love it!

I'm around 9 years with a float valve on the rodi, still waiting.